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I have some devices such as QNAP NAS drives and a computer that is not part of the domain connected to our network. I have assigned a static IP to these devices. Sometimes I find that the windows DHCP server has assigned one of these IPs to another computer which causes problems. These devices are never switched off, yet somehow the server is assigning these addresses to other machines? The VPN service also sometimes assigns these existing static ips to remote clients which prevents them from connecting to network resources.

I didn't think this should happen. I haven't set a reservation or exclusion in the DHCP server because I didn't think I should have to. There are quite a few statically assigned devices, so that would mean I would have to add all of them to be excluded.

Does anybody have any hints on how I should solve this?

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2 Answers 2

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You can have to DHCP Server check if the IP is already in use. I don't have a 2012 DHCP Server at hand but it should be in the advanced tab of settings of your dhcp server. Mine is in german but it should read like "conflict resolution".

/edit: Added an image.

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You do need to set up exclusions or reservations. DHCP does not know about any static IPs you have assigned unless you explcitly tell it.

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Ok thanks. I thought that the DHCP protocol would check if the IP existed on the network before it assigns it. –  Asagohan Sep 24 '13 at 10:35
    
Your answer is good (but chewbakka's answer allows me to do what I want to do) and I want to upvote it but I don't have enough points. –  Asagohan Sep 24 '13 at 10:52

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